> quite likely they would think poorly of me for serving them.

Mandrill sets open tracking to 'off' by default[1] and no doubt Sendgrid, et. al make it optional as well. Same goes for link tracking.

(I use Mandrill for emailing dev-related stuff and was also sensitive about this given the demographic/privacy)

https://mandrill.zendesk.com/hc/en-us/articles/205582907-How...